A/Ci on the LiCor 6400?

I'm interested in the possibility of using the LiCor 6400 gas exchange
system to measure A/Ci curves under field conditions. No instrument in
my hands yet so I can't make any guesses on the feasibility of doing
this in the field or estimate how long it will take to do a single curve
on a reasonably responsive leaf. I am particularly concerned about the
CO2 permeable cuvette gaskets-does this present a problem when making
measurements at Ca's which deviate substantially from that outside the
cuvette? Any comments from experienced users will be greatly
appreciated.